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August Imagery Quiz:
Where is this?
(Click on the above image for a full resolution image)
The first person to email us at info@e-terra.com with the correct latitude and longitude wins an iPod!
Here are a few hints:
· The image is within a 750
miles radius of Anchorage
· Located in Alaska
· north is UP
· LL84
We will present solution and a winner in the next newsletter, good luck!
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 ________________________
The Answer to July's Quiz:
(Click on image for a better image)
Last month's quiz image depicted part of the Noatak River about 15 miles upstream from the village of Noatak. 67°44'N, 162°51.5'W.
Congratulations Mark McDermott, we hope you enjoy your new iPod!
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Alaska Satellite Imagery Newsletter - August
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Greetings ,
This summer so far has been very typical, rainy with intermittent sunny days. Although, I would welcome a few more sunny days. It's hard to believe that in a week or two school will start again and fall weather will settle in. Days of crisp clear skies bring excellent opportunities to collect cloud free imagery, unfortunately low sun angles put long shadows into the picture. Of course snow and cold for another 8 months is not far behind. We would be remiss if we did not do our job and remind you that now is the time for you to coordinate and ask about data for a project, especially if it is in remote Alaska. Archive data is not always available in some parts of the state.
Brief periods of spectacular weather can easily result in forgetting the basic steps of safety and gear. This is true whether you are flying or hiking the back country. Until next month, be safe!
Sincerely,
Steve Colligan, President |
 Color Infrared (CIR) Images - Chiniak, Kodiak Island
(Click to display in higher resolution)
Above (from left to right): Chiniak true color RGB, Chiniak color infrared, Chiniak color infrared.
These 3 views are parts of a GeoEye-1 image of 50cm color 4-band data. Showing Cape Chiniak on Kodiak Island where an Air Force Base and a big runway existed. Mostly overgrown many remnants of old revetments, roads, and runway are still visible in these images. The modern day missile launch facility is about 15 miles south, situated on Narrow Cape, shore-side from Ugak Island.
Have you considered getting a Color Infrared (CIR) image in addition to natural color imagery for your project? You should, especially if information about vegetation is important to you.
All color high resolution satellites (GeoEye-1, WorldView-2, QuickBird, Ikonos) have a Near Infrared band in addition to the red, green and blue bands from the visible part of the electromagnetic spectrum. (WV-2 has even more bands).
So what is Near Infrared (NIR) and what is a Color Infrared (CIR) image?
Only a part of the radiation emitted by the sun is visible to the human eye. This part of the electromagnetic spectrum, a certain range of wavelengths, is called visible light. Near Infrared radiation has somewhat longer wavelengths than visible light. Unlike the even longer wavelength thermal infrared, NIR behaves very much like visible light, it is emitted from the sun, and when it hits the surface of the Earth, part of it is reflected and part of it is absorbed.
While a natural color image uses three bands from the visible part of the spectrum, red, green and blue, to create a color image, a color infrared (CIR) image uses the NIR, red and green bands and combines them into a color image. To make the NIR visible, it is displayed as red in the output CIR image, shifting the red and green bands to the green and blue output channels respectively.
Such a CIR or false color image looks unfamiliar at first but contains additional information about the features in the image, especially about the vegetation.
NIR radiation is reflected particularly strongly by healthy leaves, while most of the visible light is absorbed by vegetation and is used in photosynthesis. Since the NIR band is displayed as red in the CIR image, vegetation appears red in this type of image. Different shades of red can provide information about the health of trees, for example. Water usually appears dark blue or black and well defined in a CIR image.
Scattering in the atmosphere affects the NIR less than the shorter wavelengths visible light, so CIR imagery will tend to be more clear and crisp than true color imagery.
The GeoEye-1 natural color and CIR images above show a logging area on Kodiak Island in late October. Long cast shadows indicate the low sun elevation. The CIR version of the image shows the crowns of the spruce trees in red, more well-defined than in the natural color version of the image. Most of the vegetation apart from the spruce trees is dormant at this time of year and looks green or yellow in the CIR image. Roads and buildings appear in shades of grey and blue.
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Montague Island Showcase
(Click to display in higher resolution)
Above (from left to right): Montague Island from the air, Montague Island from the ground, Montague Island DigitalGlobe image, and Montague Island GeoEye image.
This is an aerial photo of the Prince William Sound side of the 50 mile long Montague Island, looking east. The island is oriented largely northeast to southwest and together with Hinchinbrook Island it shields the Prince William Sound from the prevailing southeasterly storms. Both islands have no permanent settlements, but are popular to hunters due to their bear and deer populations. With their locations weather is an issue, and Montague's nearly 3000 foot high mountain range collects incredible amounts of snow and precipitation. On this aerial photo one can see the mountains merging with the clouds, as the pilots jokingly say, "them clouds are full of rocks."
This terrestrial photo, also taken May 7, 2011, shows some clear-cut of the old logging activities that took place on Montague Island. This is overlooking MacLeod Harbor, a sheltered anchorage on the island's southwestern side. The view is exactly to the north, looking at Point Woodcock where one can see a slope-parallel logging road that is following the contour lines. The old clear-cut below the road can be seen on both the DigitalGlobe and GeoEye 17m resolution overview images showing the same part of the island as in the terrestrial photos. On the full resolution 60cm and 50cm color images one can easily count the live, dead and left behind trees.
Digital Globe's Quickbird-2, acquired an image of Montague Island five days later on May 13, 2011. The southern end of the island and the steep shoreline slope of Latouche Island can be seen across the Montague Straight. There is definitively less snow there after five days of good weather.
This GeoEye-1 image collected on May 10, 2011 is actually a mosaic of two images of the same day. The location of the terrestrial photo is at the western edge of this image. The eastern side of the island can be seen, it is exposed to the open Pacific Ocean. A prominent, if not infamous, feature there is Patton Bay which is approximately in the middle of the image. This beach is used as an airplane landing site at low tide and many planes have been wrecked there. Which in turn makes it very popular with salvage companies.
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Poster of the Month: "South of Buckland" 
(Click to display this 18 x 26 inch poster in a higher resolution preview)
This wonderfully clear mosaic of DigitalGlobe's WorldView-2 imagery shows the area south of Buckland, a village on the landlocked side of the Seward Peninsula. This area is south of the well known Selawik Lake and Buckland lies just beyond the borders of this image mosaic. The nature of this area, west of the Nulato Hills, has the typical features of the Seward Peninsula; relatively sparse low vegetation cover. Alders exist only along the drainage lines where there is enough moisture. The underlying bedrock geology provides for picturesque rock outcrops with sparse vegetation. With the comparatively thin vegetation cover one can deduct the outline of many geologic features from the air or from space. A different strata of rock creates the large, amorphic shaped darker area in the northern middle of the mosaic. There the different rock provides a different soil and thus other plants prevail here than in the rest of the area. The images are from the 27th of July 2011. |
DigitalGlobe Imagery
(Click to display in higher resolution).
Above (from left to right): Barter Island, Kenai Fjords, Homer and Seldovia, and Kiliovilik Creek.
Barter Island:
DigitalGlobe's WorldView-2 imagery of the 28th of July 2011 features the coastline of the Beaufort Sea with Barter Island. The village of Kaktovik and an Air Force installation, that was part of the Cold War's DEW-Line (Distant Early Warning) Radar stations, lies on the island. Besides being a radar station station to detect incoming unfriendly bombers, the most visible landmark features where the huge "White Alice" troposcatter communication antennas that send the gathered information inland. These were not line-of-sight radio transmitters but they send a wave form up against the troposphere where the signal would bounce off and be reflected downward. The receiving ground stations were situated a great distance beyond the horizon. The technology was like satellite communications without any satellite, but complications and cost make it completely obsolete by today's standards.
The Canadian border lies 90 miles east of Barter Island. Despite claims to the contrary, there is still ice in the Beaufort Sea. The broken up multi-year-ice lies just off-shore and is visible in the northern part of the image.
Kenai Fjords:
DigitalGlobe's Quickbird-2 imagery of the 28th of July 2011 features the coastline and mountains of the Kenai Fjords with the Harding Icefield, Dinglestadt and McCarty Glaciers. The extensively glaciated Kenai Mountains are beautiful from all directions, however the seaside to the south is the most splendid and the least visited part of this wilderness. With no roads or settlements this area is only accessible by bush-plane or boat in rough North Pacific waters.
Homer and Seldovia:
DigitalGlobe's WorldView-2 imagery of the 22nd of July, 2011 features the southwestern Kenai Peninsula and Kachemak Bay area. Homer lies at the eastern (right side) edge of the image and Anchor Point is just beyond the western edge of the image. The village of Seldovia lies approximately in the middle of the image; whereas, the partially visible airport of the village of Port Graham is at the western edge of the image. In the past the economy was more about logging and fishing than about tourism, as it is now. Back then many more settlements and airstrips existed on the southern shoreline of Kachemak Bay.
Kiliovilik Creek:
DigitalGlobe's WorldView-2 imagery of the 27th of July 2011 shows the Kiliovilik Creek in the Sheklukshuk Range, north of the Purcell Mountains. This area lies south of Shungnak, the village on the Kobuk River. The Lockwood Hills, known for mapping errors, are east of this area. The Purcell Mountains and the Zane Hills form the Continental Divide, south of this area. The Kiliovilik Creek drains into Selawik Lake.
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GeoEye Imagery 
(Click to display in higher resolution).
Above (from left to right): Southern Shore of Lake Illiamna, Canada in Stereo, and Mexico in Stereo.
Beluga River
This GeoEye-1 50cm color images was taken on the 29th of July 2011. Taken between rain showers the sky was crisp and clear and great atmospheric conditions make for extraordinary image quality. On the overview image one can see the large meandering Beluga River in the southern part of the image. Lower Beluga Lake lies just to the west of the edge of this image.
The Beluga River is a very short river for its size and it carries a large quantity of water due to Beluga Lake being fed by the vast Triumvirate Glacier and its tributaries. Lower Beluga Lake is essentially a wide spot in the river and technically not a real lake. The Beluga Power Plant and runway lies just to the south of this image and are covered by another GeoEye-1 image from the 26th of June 2011. The smaller meandering river in the northeastern side of the image is the Theodore River. The road system visible in the image is a local oil and gas exploration affair, it has no connection to the public road system and Anchorage.
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| About E-Terra, LLC
Founded in 1994, E-Terra is a skilled team of technology professionals with wide ranging expertise in computer solutions and products. E-Terra's knowledge of Geographic Information Systems (GIS), Databases, the Internet, and CAD systems provides you with complete solutions tailored to your specific needs. |
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